Supply modulator and wireless communication apparatus including the same

Abstract

Provided are a supply modulator and a wireless communication apparatus including the same. A supply modulator according to the inventive concept is driven in any one of an average power tracking mode and a discrete level envelope tracking mode to apply an output voltage to a power amplifier, and includes a multiple output voltage balancer, a switching regulator, a switching regulator controller, a switch array, a discrete-level controller, a switch controller, an output filter, and a main controller.

What is claimed is: 
     
       1. A supply modulator driven to apply an output voltage to a power amplifier, the supply modulator comprising:
 a switching regulator outputting a first current to generate the output voltage in a discrete level envelope tracking mode or an average power tracking mode; 
 a multiple output voltage balancer operating together with the switching regulator in the discrete level envelope tracking mode, and configured to output a plurality of voltages having different levels of which the difference is equally adjusted based on the first current received from the switching regulator; 
 a switch array comprising a plurality of switches respectively corresponding to the plurality of voltages having different levels output from the multiple output voltage balancer, and configured to select one of the plurality of voltages having different levels and apply the selected voltage to the power amplifier; and 
 a main controller configured to select one of the average power tracking mode and the discrete level envelope tracking mode, and control the multiple output voltage balancer based on the selected tracking mode, 
 wherein, in the discrete level envelope tracking mode, the output voltage is generated based on a sum current of the first current and a second current provided through the switch array. 
 
     
     
       2. The supply modulator of  claim 1 , wherein the switching regulator controls a level of the first current such that an average of the second current is approximately 0. 
     
     
       3. The supply modulator of  claim 1 , wherein the multiple output voltage balancer generates the output voltage without receiving a power supply from an outside power source. 
     
     
       4. The supply modulator of  claim 1 , wherein the levels of the plurality of voltages are adjusted by boosting and reducing the first current. 
     
     
       5. The supply modulator of  claim 1 , further comprising a switching regulator controller configured to sense the second current in the discrete level envelope tracking mode and control the switching regulator based on a sensing value. 
     
     
       6. The supply modulator of  claim 5 , further comprising:
 a discrete-level controller configured to generate a level control signal based on a digital envelope signal received from outside; 
 a switch controller configured to receive the level control signal from the discrete-level controller, and control opening and closing operations of the plurality of switches based on the received level control signal. 
 
     
     
       7. The supply modulator of  claim 6 , further comprising:
 a feedback loop configured to sense the second current; 
 a first comparator configured to compare any one of the plurality of voltages having different levels with a reference output voltage signal to output a difference value; 
 a summer configured to sum the difference value output from the first comparator and a sensing value sensed by the feedback loop to output a summed value as a compensation value; and 
 a second comparator configured to compare the compensation value output from the summer with a reference value and output a result of the comparing as a switching regulator control signal to the switching regulator. 
 
     
     
       8. The supply modulator of  claim 7 , wherein the multiple output voltage balancer comprises:
 a plurality of load capacitors each corresponding to a difference between the plurality of voltages having different levels; 
 a plurality of balance switch sets corresponding to the plurality of load capacitors; and 
 a plurality of flying capacitors configured to adjust a balance of voltages applied to the plurality of load capacitors along with the plurality of balance switch sets, 
 wherein each of the plurality of balance switch sets comprises a pair of balance switches that are alternately turned on and turned off. 
 
     
     
       9. The supply modulator of  claim 8 , wherein, in the average power tracking mode,
 the switch controller is further configured to control at least one of the plurality of switches and connect a corresponding load capacitor from among the plurality of load capacitors to the power amplifier. 
 
     
     
       10. The supply modulator of  claim 1 , wherein the multiple output voltage balancer is connected in parallel with the switching regulator. 
     
     
       11. The supply modulator of  claim 1 , wherein the first current comprises current of a low-frequency component and the second current comprises current of a high-frequency component. 
     
     
       12. The supply modulator of  claim 1 , further comprising an output filter configured to remove noise from the output voltage,
 wherein, in the average power tracking mode, the switching regulator generates a regulated voltage based on control by the main controller, and 
 wherein the supply modulator outputs the regulated voltage from which the noise is removed as the output voltage. 
 
     
     
       13. A wireless communication apparatus comprising:
 a modem configured to process a baseband signal and generate an envelope signal corresponding to an envelope of the baseband signal; 
 a supply modulator configured to generate an output voltage whose level dynamically varies based on the envelope signal; and 
 a power amplifier configured to amplify the output voltage from the supply modulator, 
 wherein the supply modulator comprises: 
 a switching regulator outputting a first current to generate the output voltage in a discrete level envelope tracking mode or an average power tracking mode;
 a multiple output voltage balancer operating together with the switching regulator in the discrete level envelope tracking mode, and configured to output a plurality of voltages having different levels of which the difference is equally adjusted based on the first current received from the switching regulator; 
 a switch array comprising a plurality of switches respectively corresponding to the plurality of voltages having different levels output from the multiple output voltage balancer, and configured to select one of the plurality of voltages having different levels and apply the selected voltage to the power amplifier; and 
 a main controller configured to select one of the average power tracking mode and the discrete level envelope tracking mode, and control the multiple output voltage balancer based on the selected tracking mode. 
 
 
     
     
       14. The wireless communication apparatus of  claim 13 , wherein the supply modulator further comprises an output filter configured to remove noise from the output voltage,
 wherein, in the average power tracking mode, the switching regulator generates a regulated voltage based on control by the main controller, and 
 wherein the supply modulator outputs the regulated voltage from which the noise is removed as the output voltage.